This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: When two black holes crash together and merge, the newly formed black hole rings like a bell, sending out gravitational waves with specific frequencies that fade over time. This brief, fading pattern of waves is called ringdown, and it may hold secrets about what is hiding around black holes.
According to Einstein's basic rules for the simplest kind of black hole, ringdown waves depend only on two things: a black hole's mass and how fast it spins. But what if black holes have hidden matter around them? If so, this matter would also affect the characteristics of the ringdown waves.
As a result, ringdown may hold information about hidden matter surrounding the black hole. In theoretical physics, this extra structure is often called "black hole hair." A team led by researchers from Nagoya University in Japan has found a way to check for hair using changes in ringdown waves. They found that hidden matter does not affect these waves uniformly; the frequency and fade-out speed of the waves respond differently.
This difference may show whether hidden matter is present and how its pressure is arranged around a black hole. For spinning black holes, hidden matter affects ringdown differently, depending on whether the waves move with or against the black hole's spin. Published in the Journal of Cosmology and Astroparticle Physics, the study identifies a pattern in the gravitational wave signal that would be a clue that hidden hair is present and may help future observations tell a hairy black hole apart from an ordinary one.
Scientists continue testing whether Einstein's theory of general relativity perfectly describes black holes and what deviations may exist. Finding signs of black hole hair is difficult because different kinds of extra matter or new physics can change the ringdown in different ways. This study gives researchers a clearer idea of what patterns to look for in future ringdown data.
"Black hole hair may represent matter surrounding the black hole or deviations from the simplest kind of black hole predicted by general relativity. Because these may slightly change the ringdown signal, detecting or ruling out these changes could give us a new way to test gravity in this extreme region," said first author Ariadna Uxue Palomino Ylla, a Ph.D. student from Nagoya University's Graduate School of Science. A black hole distorts spacetime so severely that it bends the paths of light and gravitational waves.
Extract — continue reading at the source.
